Baghdad — There is little ambiguity in President Obama's plan for an accelerated US withdrawal from Iraq: By August next year the combat mission will be over. By the end of 2011 all US troops are intended to be gone.

US officials emphasize there are no current plans to keep American forces here past 2011. But as US forces shift gears to advisory and training roles, after six years of combat, the continuing insurgency and Iraq's budget crunch could cause Iraq and the US to rethink that plan.

While Iraq's security forces have improved dramatically, a wide variety of US officials interviewed for this article question whether they will be able to maintain hard-won gains in the face of a low-level insurgency expected to continue for years to come.

"The question is can the Iraqis keep it down without us being here, and we would assess right now that they cannot," says a senior US military official who asked to remain anonymous to be able to speak more freely. Iraq's security forces "are clearly better than they were, but they still do not have the capability to be their own self-sufficient counterinsurgency force."

That could mean that the US training force left after August 2010 would transition into a continuing military presence similar to those found elsewhere in the region. "I have very little doubt that the Iraqi government in 2011 will ask for some advisers to stay and I have very little doubt that the American government will honor that request," says John Nagl, a counterinsurgency expert and president of the Center for a New American Security, a Washington-based think tank.

Fighting an enemy that blends in

Unlike conventional warfare, fighting an enemy that blends into the population relies heavily on intelligence and on removing the reasons that people tolerate or support insurgents among them – everything from intimidation to unemployment.

Last year's surge of US and Iraqi troops was part of a counterinsurgency campaign aimed at not just killing and capturing insurgents but also protecting and winning the support of the population. Along with Sunni fighters turning against Al Qaeda in Iraq and a cease-fire by the Mahdi Army, the campaign led to a dramatic drop in violence. The senior US official, though, says low-level insurgencies such as Iraq's can last for years.

While the Iraqi Army has become relatively adept at conventional operations and has improved its planning and logistics, much of the drop in attacks over the past year has been achieved through counterinsurgency and counterterrorism operations increasingly partnered with Iraqi troops but still led by US forces.

"I think the Iraqis know that there are some things that have to occur before we leave; they know there are some capabilities they have to develop," says another senior commander, speaking on background. "I think they'll be up to task when we do leave 2011 but … whether or not they'll come here and ask us for other help or training is left to be seen."

What Iraqi security forces need

A budget crunch sparked by a steep drop in oil prices could also slow efforts by Iraqi security forces to fully operate on their own and fight the insurgency, says the latest Pentagon report.

Already a hiring freeze by the Iraqi government has stalled plans to increase the size of its security forces from 615,000 to about 646,000.

Iraqi security forces still rely on the US for combat and logistical help, including close air support, communications, intelligence and surveillance, as well as clearance of roadside bombs and medical support.

"In particular they don't have the technical intelligence assets that we do in order to eavesdrop on what the insurgents are saying," says Dr. Nagl, who as a US Army officer helped develop the military's latest counterinsurgency manual. "It's easier to share the products of our intelligence equipment rather than the equipment itself," which he characterizes as "the highest-end stuff we've got" and unlikely to be shared with Iraq.

"I'm confident that [the Iraqi security forces can ultimately stand on their own] but I would say we have a fair amount of work to do before they reach that point," said Lt. Gen. Lloyd Austin, in charge of ground forces in Iraq, after relinquishing command this month to a new Corps commander.

External threats not as urgent

The top US commander in Iraq, Gen. Raymond Odierno, says he believes equipment needed to modernize the Iraqi military is largely geared at external threats rather than internal security and can likely wait until past 2011.

"Whether they're able to modernize their Army, Navy, and Air Force by 2011 is unknown because that's going to be based on the ability of their budget," said General Odierno in a recent Monitor interview.

Among the implicit assumptions are that the US will continue to protect Iraqi airspace past 2011, particularly in light of concern over neighboring Iran. The US essentially destroyed Iraq's Air Force in the 2003 war.

"I find it unlikely that the Iraqis will have control over their airspace in 2011 when in April 2009 they have no jet aircraft – none," says Nagl.

Iraq committed $2.72 billion last year to buying US weapons but will likely delay a range of purchases including armored vehicles, mortars, and equipment, and the training needed to sustain systems they have.

"Part of what I think they're struggling with is a full and robust set of capabilities that they would like to purchase and maybe less than sufficient means to purchase all the things they want," says Brig. Gen. Charles Luckey.